L86- Pituitary Pathology

Question 1

Describe the general locations of cells within the “Adenohypothesis” aka Anterior pituitary.

Answer 1

Anterior Pituitary has cells that make LH, FSH, Prolactin, TSH, Growth hormone and ACTH in the following distribution (see picture):

ACTH and TSH are more midline as is the Posterior Pituitary

GH/PRL are more lateral flanks

Question 2

What is the main clinical manifestation of the Neoplasms of the Pituitary?

Answer 2

Bitemporal Hemianopsia!!! Pituitary adneoma!!!

Question 3

What do you see cellularly in the posterior pituitary? What is the funny name for these features and what’s inside of them?

Answer 3

Terminal Axon Swellings (Boutons) filled w/ ADH and Oxytocin = Herring Bodies!

Question 4

In general, describe what the histology of normal pituitary looks like compared to an adenoma - broad terms here.

Answer 4

Anterior Pituitary normally shows lots of colors bc clusters of cells making lots of different hormones

• Mixed Cells and Nested ARchitecture

vs

Adenoma is more clonal and uniform and only 1 color!

• cytoplasmic uniformity and no nested cell architecture

Question 5

What is the pathological effect of a Null-cell adenoma or one that is hypofunctioning?

Answer 5

MASS effect!!! and often it causes hypo-functioning of other pituitary cells bc of the mass effect

Question 6

Micro vs Macro adenoma? Which cell types tend tobe smaller?

Answer 6

Macro-adenoma > 1 cm and Microadeboma < 1cm

ACTH producing tumors tend to be small/microadenomas that can invade cavernous sinus and cause hydrocephalus! Yikes!

Question 7

What is the MOST COMMON functional tumor of the anterior pituitary? What does it secrete? How can you use the levels of this hormone to correlate to pathology? What is the exception?

Answer 7

Prolactinoma!

Serum Prolactin correlates w/ Tumor Size:

• elevation proportional to tumor size

BUTTTTT if there can also be large tumor and only little Prolactin elevation = Stalk effect –> Compress stalk and stop release of normal inhibitory Da onto pituitary

• therefore wont respond to Bromocriptine!

Stalk Effect: (NON-Tumor) damage to stalk to stop inhibitory Da = mild hyper–prolactinemia

Question 8

What are the clinical signs of a Prolactinoma?

Answer 8

Amenorrhea

Galactorrhea

Loss of libido

Infertility

Menstural abnormalities

Question 9

Describe the symptoms of Acromegaly?

Answer 9

Galactorrhea and sexual dysfunction - GH can co-produce Prolactin

Cardiomegaly and HTN

Peripheral neuropathy

Face growing and bone growing stufffffffff

Sausage fingers hahaa

Abnormal Glucose Tolerance and Glucosuria! - Insulin resistance

Question 10

What is the second most common functional neoplasm? What can it co-express? How do you treat it?

What does persistent hypersecretion lead to….

Answer 10

Somatotroph Adenoma - causes Acromegaly and Gigantism

Co-expression of Prolactin seen

Medical Tx - Octreotide

Persistent hypersecretion of GH stimulates hepatic secretion of IGF-1 leading to insulin resistance

Question 11

Cushing’s Disease - what’s happening there? Disease vs Syndrome? Who gets it?

Answer 11

Cushing Disease - small tumor in sella causing pituitary hypersecretion of ACTH (vs syndrome which is non-pituitary source)

Females > Males

ACTH producing adenoma that leads to hyperplastic adrenals secondarily

Question 12

What are the pathological findings for a Corticotroph adenoma?

Answer 12

Often small Microadenoma (< 1cm)

Basophilic

_*Crooke’s Hyaline Change_ - cells lose granules and gain cytokeratin filaments in cytoplasms of the non-neoplastic ACTH cells bc too much Cortisol causing negative feedback on them but not on the tumor cells

Question 13

What are other functioning adenomas of the pituitary?

Answer 13

Gonadotroph Adenomas - LH/FSH present in middle aged people

• gonadotroph deficiency often paradoxically present bc adenoma destroying pituitary moreso than secreting

Thyrotroph Adenoma - 1% of all adenoma - rare cause of central hyperthyroidism

• high TSH levels in the face of High Thyroxin

Question 14

What do you need to diagnose pituitary carcinoma?

Answer 14

Metastatic disease - very rare

Question 15

How much pituiary has to be destroyed to see hypopituitarism? What are some causes of it?

Answer 15

75% destruction and causes include:

• neoplasia/cysts
• Apoplexy - hemorrhage into an ademona (excruciating HA)
• Ischemia
• DIC
• Sickle Cell
• Elevatd Itracranial pressure
• Trauma and radiation

- Empty Sella Syndrome

- Rathke’s Cleft Cyst!!!

Question 16

What is empty sella syndrome?

Answer 16

Herniation of arachnoid tissue through defect in sellar diaphragm into sella

can expand and see empty sella bc looks devoid of contents but not really empty bc herniation of arachnoid in there

Question 17

What is a “SupraSellar Tumor” ? Who gets them? What are the buzzwords for this? Subtypes?

Answer 17

Craniopharyngioma - 5% intracranial tumors

Kids and young people

Slow growing but difficult to resect:

Buzzwords:

• on imaging/grossly see Cystic w/ Calcifications
• Machinery Oil-like cyst fluid
• tooth remnants from walls of Rathkes cleft - tumors of mandible-like - Odontogenic Tumor
• Peripheral Palisading, Stellate, Wet Keratin

Subtypes: Adamantinomatous (more common) and Papillary

Question 18

What are the 2 posterior Pituitary Syndromes we leanred about and how do you get them and how do they present? commee onnnnn…..easssyyyyy

Answer 18

1) Diabetes Insipidus - presents w/ polyuria, polydipsia, inability to concentrate urine, Hypernatremia

Causes include - Trauma (surgery), tumors, inflammatory disorders

2) Syndrome of Inappropriate ADH secretions - Hyponatremia, cerebral edema and neurologic dysfunction

Causes include - Small cell carcinoma/paraneoplastic, TB, Pneumonia, injury to hypothalamus